Sheepdogs are again a common sight on farms around the country but there are concerns the art of training them is dying out.

Demand is growing as farmers flock back to the traditional method of moving stock.

But the skill, cost and time it takes to train them is proving a problem.

Tasmania's top dogs have gathered in the north of the state for Agfest one of the biggest rural expos in the country.

Since 1983, the annual three-day event has showcased the latest in farming technology.

It is also the best spot in Tasmania to pick a future champion sheepdog.

Breeder and nine time national representative Malcolm Taylor knows the value of a quality sheepdog more than most.

He is raising nine dogs on his property at Deloraine in northern Tasmania.

"People, when they buy a broken in dog, can see what he's gonna be like when they buy him."

Mr Taylor says farmers have realised sheepdogs are the only effective way to manage stock and demand has skyrocketed.

"He can think things that we can't even think and a motorbike is really only a source of travelling around a paddock."

"It's not a working machine like a dog is," he said.

The problem is many farmers have lost the skill and patience needed to train puppies and dogs are not ready to work until they are three years old.

The President of the Tasmanian Working Dogs Association, Bernard McGlashan, says dog trainers are struggling to keep up with demand.

"A lot of farmers these days can't afford the time with pups, to train pups, so they're looking for the dog that's started and training, so they can go from here to there very quickly and have a working dog," he said.

It is led to stiff competition both on the farm and in the ring, with some mature dogs fetching as much as $5,000.

And it's not just sheep dogs farmers are after.

"There's a big demand for dogs for dairy farmers, cattle workers, they all want dogs. Getting the type of dog to suit them is probably the hardest thing," Mr Taylor says.

For the dogs at Agfest, they have only one thing on their mind - a place in the national team.

More than 100 dogs will be put through their paces, as the nerves of the animals and their owners will be put to the test.